/* add a key to a secret keyring */
int
pgp_add_to_secring(pgp_keyring_t *keyring, const pgp_seckey_t *seckey)
{
const pgp_pubkey_t *pubkey;
pgp_key_t *key;
if (pgp_get_debug_level(__FILE__)) {
fprintf(stderr, "pgp_add_to_secring\n");
}
if (keyring->keyc > 0) {
key = &keyring->keys[keyring->keyc - 1];
if (pgp_get_debug_level(__FILE__) &&
key->key.pubkey.alg == PGP_PKA_DSA &&
seckey->pubkey.alg == PGP_PKA_ELGAMAL) {
fprintf(stderr, "pgp_add_to_secring: found elgamal seckey\n");
}
}
EXPAND_ARRAY(keyring, key);
key = &keyring->keys[keyring->keyc++];
(void) memset(key, 0x0, sizeof(*key));
pubkey = &seckey->pubkey;
pgp_keyid(key->sigid, PGP_KEY_ID_SIZE, pubkey, keyring->hashtype);
pgp_fingerprint(&key->sigfingerprint, pubkey, keyring->hashtype);
key->type = PGP_PTAG_CT_SECRET_KEY;
key->key.seckey = *seckey;
if (pgp_get_debug_level(__FILE__)) {
fprintf(stderr, "pgp_add_to_secring: keyc %u\n", keyring->keyc);
}
return 1;
}
/* add a key to a public keyring */
int
pgp_add_to_pubring(pgp_keyring_t *keyring, const pgp_pubkey_t *pubkey, pgp_content_enum tag)
{
pgp_key_t *key;
time_t duration;
if (pgp_get_debug_level(__FILE__)) {
fprintf(stderr, "pgp_add_to_pubring (type %u)\n", tag);
}
switch(tag) {
case PGP_PTAG_CT_PUBLIC_KEY:
EXPAND_ARRAY(keyring, key);
key = &keyring->keys[keyring->keyc++];
duration = key->key.pubkey.duration;
(void) memset(key, 0x0, sizeof(*key));
key->type = tag;
pgp_keyid(key->sigid, PGP_KEY_ID_SIZE, pubkey, keyring->hashtype);
pgp_fingerprint(&key->sigfingerprint, pubkey, keyring->hashtype);
key->key.pubkey = *pubkey;
key->key.pubkey.duration = duration;
return 1;
case PGP_PTAG_CT_PUBLIC_SUBKEY:
/* subkey is not the first */
key = &keyring->keys[keyring->keyc - 1];
pgp_keyid(key->encid, PGP_KEY_ID_SIZE, pubkey, keyring->hashtype);
duration = key->key.pubkey.duration;
(void) memcpy(&key->enckey, pubkey, sizeof(key->enckey));
key->enckey.duration = duration;
return 1;
default:
return 0;
}
}
int dc_pgp_calc_fingerprint(const dc_key_t* raw_key, uint8_t** ret_fingerprint, size_t* ret_fingerprint_bytes)
{
int success = 0;
pgp_keyring_t* public_keys = calloc(1, sizeof(pgp_keyring_t));
pgp_keyring_t* private_keys = calloc(1, sizeof(pgp_keyring_t));
pgp_memory_t* keysmem = pgp_memory_new();
if (raw_key==NULL || ret_fingerprint==NULL || *ret_fingerprint!=NULL || ret_fingerprint_bytes==NULL || *ret_fingerprint_bytes!=0
|| raw_key->binary==NULL || raw_key->bytes <= 0
|| public_keys==NULL || private_keys==NULL || keysmem==NULL) {
goto cleanup;
}
pgp_memory_add(keysmem, raw_key->binary, raw_key->bytes);
pgp_filter_keys_from_mem(&s_io, public_keys, private_keys, NULL, 0, keysmem);
if (raw_key->type != DC_KEY_PUBLIC || public_keys->keyc <= 0) {
goto cleanup;
}
pgp_key_t* key0 = &public_keys->keys[0];
pgp_pubkey_t* pubkey0 = &key0->key.pubkey;
if (!pgp_fingerprint(&key0->pubkeyfpr, pubkey0, 0)) {
goto cleanup;
}
*ret_fingerprint_bytes = key0->pubkeyfpr.length;
*ret_fingerprint = malloc(*ret_fingerprint_bytes);
memcpy(*ret_fingerprint, key0->pubkeyfpr.fingerprint, *ret_fingerprint_bytes);
success = 1;
cleanup:
if (keysmem) { pgp_memory_free(keysmem); }
if (public_keys) { pgp_keyring_purge(public_keys); free(public_keys); } /*pgp_keyring_free() frees the content, not the pointer itself*/
if (private_keys) { pgp_keyring_purge(private_keys); free(private_keys); }
return success;
}
int dc_pgp_create_keypair(dc_context_t* context, const char* addr, dc_key_t* ret_public_key, dc_key_t* ret_private_key)
{
int success = 0;
pgp_key_t seckey;
pgp_key_t pubkey;
pgp_key_t subkey;
uint8_t subkeyid[PGP_KEY_ID_SIZE];
uint8_t* user_id = NULL;
pgp_memory_t* pubmem = pgp_memory_new();
pgp_memory_t* secmem = pgp_memory_new();
pgp_output_t* pubout = pgp_output_new();
pgp_output_t* secout = pgp_output_new();
memset(&seckey, 0, sizeof(pgp_key_t));
memset(&pubkey, 0, sizeof(pgp_key_t));
memset(&subkey, 0, sizeof(pgp_key_t));
if (context==NULL || addr==NULL || ret_public_key==NULL || ret_private_key==NULL
|| pubmem==NULL || secmem==NULL || pubout==NULL || secout==NULL) {
goto cleanup;
}
/* Generate User ID.
By convention, this is the e-mail-address in angle brackets.
As the user-id is only decorative in Autocrypt and not needed for Delta Chat,
so we _could_ just use sth. that looks like an e-mail-address.
This would protect the user's privacy if someone else uploads the keys to keyservers.
However, as eg. Enigmail displayes the user-id in "Good signature from <user-id>,
for now, we decided to leave the address in the user-id */
#if 0
user_id = (uint8_t*)dc_mprintf("<%08X@%08X.org>", (int)random(), (int)random());
#else
user_id = (uint8_t*)dc_mprintf("<%s>", addr);
#endif
/* generate two keypairs */
if (!pgp_rsa_generate_keypair(&seckey, DC_KEYGEN_BITS, DC_KEYGEN_E, NULL, NULL, NULL, 0)
|| !pgp_rsa_generate_keypair(&subkey, DC_KEYGEN_BITS, DC_KEYGEN_E, NULL, NULL, NULL, 0)) {
goto cleanup;
}
/* Create public key, bind public subkey to public key
------------------------------------------------------------------------ */
pubkey.type = PGP_PTAG_CT_PUBLIC_KEY;
pgp_pubkey_dup(&pubkey.key.pubkey, &seckey.key.pubkey);
memcpy(pubkey.pubkeyid, seckey.pubkeyid, PGP_KEY_ID_SIZE);
pgp_fingerprint(&pubkey.pubkeyfpr, &seckey.key.pubkey, 0);
add_selfsigned_userid(&seckey, &pubkey, (const uint8_t*)user_id, 0/*never expire*/);
EXPAND_ARRAY((&pubkey), subkey);
{
pgp_subkey_t* p = &pubkey.subkeys[pubkey.subkeyc++];
pgp_pubkey_dup(&p->key.pubkey, &subkey.key.pubkey);
pgp_keyid(subkeyid, PGP_KEY_ID_SIZE, &pubkey.key.pubkey, PGP_HASH_SHA1);
memcpy(p->id, subkeyid, PGP_KEY_ID_SIZE);
}
EXPAND_ARRAY((&pubkey), subkeysig);
add_subkey_binding_signature(&pubkey.subkeysigs[pubkey.subkeysigc++], &pubkey, &subkey, &seckey);
/* Create secret key, bind secret subkey to secret key
------------------------------------------------------------------------ */
EXPAND_ARRAY((&seckey), subkey);
{
pgp_subkey_t* p = &seckey.subkeys[seckey.subkeyc++];
pgp_seckey_dup(&p->key.seckey, &subkey.key.seckey);
pgp_keyid(subkeyid, PGP_KEY_ID_SIZE, &seckey.key.pubkey, PGP_HASH_SHA1);
memcpy(p->id, subkeyid, PGP_KEY_ID_SIZE);
}
EXPAND_ARRAY((&seckey), subkeysig);
add_subkey_binding_signature(&seckey.subkeysigs[seckey.subkeysigc++], &seckey, &subkey, &seckey);
/* Done with key generation, write binary keys to memory
------------------------------------------------------------------------ */
pgp_writer_set_memory(pubout, pubmem);
if (!pgp_write_xfer_key(pubout, &pubkey, 0/*armored*/)
|| pubmem->buf==NULL || pubmem->length <= 0) {
goto cleanup;
}
pgp_writer_set_memory(secout, secmem);
if (!pgp_write_xfer_key(secout, &seckey, 0/*armored*/)
|| secmem->buf==NULL || secmem->length <= 0) {
goto cleanup;
}
dc_key_set_from_binary(ret_public_key, pubmem->buf, pubmem->length, DC_KEY_PUBLIC);
dc_key_set_from_binary(ret_private_key, secmem->buf, secmem->length, DC_KEY_PRIVATE);
success = 1;
cleanup:
if (pubout) { pgp_output_delete(pubout); }
if (secout) { pgp_output_delete(secout); }
if (pubmem) { pgp_memory_free(pubmem); }
if (secmem) { pgp_memory_free(secmem); }
pgp_key_free(&seckey); /* not: pgp_keydata_free() which will also free the pointer itself (we created it on the stack) */
pgp_key_free(&pubkey);
pgp_key_free(&subkey);
free(user_id);
return success;
}
int dc_pgp_pk_decrypt( dc_context_t* context,
const void* ctext,
size_t ctext_bytes,
const dc_keyring_t* raw_private_keys_for_decryption,
const dc_keyring_t* raw_public_keys_for_validation,
int use_armor,
void** ret_plain,
size_t* ret_plain_bytes,
dc_hash_t* ret_signature_fingerprints)
{
pgp_keyring_t* public_keys = calloc(1, sizeof(pgp_keyring_t)); /*should be 0 after parsing*/
pgp_keyring_t* private_keys = calloc(1, sizeof(pgp_keyring_t));
pgp_keyring_t* dummy_keys = calloc(1, sizeof(pgp_keyring_t));
pgp_validation_t* vresult = calloc(1, sizeof(pgp_validation_t));
key_id_t* recipients_key_ids = NULL;
unsigned recipients_cnt = 0;
pgp_memory_t* keysmem = pgp_memory_new();
int i = 0;
int success = 0;
if (context==NULL || ctext==NULL || ctext_bytes==0 || ret_plain==NULL || ret_plain_bytes==NULL
|| raw_private_keys_for_decryption==NULL || raw_private_keys_for_decryption->count<=0
|| vresult==NULL || keysmem==NULL || public_keys==NULL || private_keys==NULL) {
goto cleanup;
}
*ret_plain = NULL;
*ret_plain_bytes = 0;
/* setup keys (the keys may come from pgp_filter_keys_fileread(), see also pgp_keyring_add(rcpts, key)) */
for (i = 0; i < raw_private_keys_for_decryption->count; i++) {
pgp_memory_clear(keysmem); /* a simple concatenate of private binary keys fails (works for public keys, however, we don't do it there either) */
pgp_memory_add(keysmem, raw_private_keys_for_decryption->keys[i]->binary, raw_private_keys_for_decryption->keys[i]->bytes);
pgp_filter_keys_from_mem(&s_io, dummy_keys/*should stay empty*/, private_keys, NULL, 0, keysmem);
}
if (private_keys->keyc<=0) {
dc_log_warning(context, 0, "Decryption-keyring contains unexpected data (%i/%i)", public_keys->keyc, private_keys->keyc);
goto cleanup;
}
if (raw_public_keys_for_validation) {
for (i = 0; i < raw_public_keys_for_validation->count; i++) {
pgp_memory_clear(keysmem);
pgp_memory_add(keysmem, raw_public_keys_for_validation->keys[i]->binary, raw_public_keys_for_validation->keys[i]->bytes);
pgp_filter_keys_from_mem(&s_io, public_keys, dummy_keys/*should stay empty*/, NULL, 0, keysmem);
}
}
/* decrypt */
{
pgp_memory_t* outmem = pgp_decrypt_and_validate_buf(&s_io, vresult, ctext, ctext_bytes, private_keys, public_keys,
use_armor, &recipients_key_ids, &recipients_cnt);
if (outmem==NULL) {
dc_log_warning(context, 0, "Decryption failed.");
goto cleanup;
}
*ret_plain = outmem->buf;
*ret_plain_bytes = outmem->length;
free(outmem); /* do not use pgp_memory_free() as we took ownership of the buffer */
// collect the keys of the valid signatures
if (ret_signature_fingerprints)
{
for (i = 0; i < vresult->validc; i++)
{
unsigned from = 0;
pgp_key_t* key0 = pgp_getkeybyid(&s_io, public_keys, vresult->valid_sigs[i].signer_id, &from, NULL, NULL, 0, 0);
if (key0) {
pgp_pubkey_t* pubkey0 = &key0->key.pubkey;
if (!pgp_fingerprint(&key0->pubkeyfpr, pubkey0, 0)) {
goto cleanup;
}
char* fingerprint_hex = dc_binary_to_uc_hex(key0->pubkeyfpr.fingerprint, key0->pubkeyfpr.length);
if (fingerprint_hex) {
dc_hash_insert(ret_signature_fingerprints, fingerprint_hex, strlen(fingerprint_hex), (void*)1);
}
free(fingerprint_hex);
}
}
}
}
success = 1;
cleanup:
if (keysmem) { pgp_memory_free(keysmem); }
if (public_keys) { pgp_keyring_purge(public_keys); free(public_keys); } /*pgp_keyring_free() frees the content, not the pointer itself*/
if (private_keys) { pgp_keyring_purge(private_keys); free(private_keys); }
if (dummy_keys) { pgp_keyring_purge(dummy_keys); free(dummy_keys); }
if (vresult) { pgp_validate_result_free(vresult); }
free(recipients_key_ids);
return success;
}
/**
\ingroup HighLevel_KeyGenerate
\brief Generates an RSA keypair
\param numbits Modulus size
\param e Public Exponent
\param keydata Pointer to keydata struct to hold new key
\return 1 if key generated successfully; otherwise 0
\note It is the caller's responsibility to call pgp_keydata_free(keydata)
*/
static unsigned
rsa_generate_keypair(pgp_key_t *keydata,
const int numbits,
const unsigned long e,
const char *hashalg,
const char *cipher)
{
pgp_seckey_t *seckey;
RSA *rsa;
BN_CTX *ctx;
pgp_output_t *output;
pgp_memory_t *mem;
ctx = BN_CTX_new();
pgp_keydata_init(keydata, PGP_PTAG_CT_SECRET_KEY);
seckey = pgp_get_writable_seckey(keydata);
/* generate the key pair */
rsa = RSA_generate_key(numbits, e, NULL, NULL);
/* populate pgp key from ssl key */
seckey->pubkey.version = PGP_V4;
seckey->pubkey.birthtime = time(NULL);
seckey->pubkey.days_valid = 0;
seckey->pubkey.alg = PGP_PKA_RSA;
seckey->pubkey.key.rsa.n = BN_dup(rsa->n);
seckey->pubkey.key.rsa.e = BN_dup(rsa->e);
seckey->s2k_usage = PGP_S2KU_ENCRYPTED_AND_HASHED;
seckey->s2k_specifier = PGP_S2KS_SALTED;
/* seckey->s2k_specifier=PGP_S2KS_SIMPLE; */
if ((seckey->hash_alg = pgp_str_to_hash_alg(hashalg)) == PGP_HASH_UNKNOWN) {
seckey->hash_alg = PGP_HASH_SHA1;
}
seckey->alg = pgp_str_to_cipher(cipher);
seckey->octetc = 0;
seckey->checksum = 0;
seckey->key.rsa.d = BN_dup(rsa->d);
seckey->key.rsa.p = BN_dup(rsa->p);
seckey->key.rsa.q = BN_dup(rsa->q);
seckey->key.rsa.u = BN_mod_inverse(NULL, rsa->p, rsa->q, ctx);
if (seckey->key.rsa.u == NULL) {
(void) fprintf(stderr, "seckey->key.rsa.u is NULL\n");
return 0;
}
BN_CTX_free(ctx);
RSA_free(rsa);
pgp_keyid(keydata->sigid, PGP_KEY_ID_SIZE, &keydata->key.seckey.pubkey, seckey->hash_alg);
pgp_fingerprint(&keydata->sigfingerprint, &keydata->key.seckey.pubkey, seckey->hash_alg);
/* Generate checksum */
output = NULL;
mem = NULL;
pgp_setup_memory_write(&output, &mem, 128);
pgp_push_checksum_writer(output, seckey);
switch (seckey->pubkey.alg) {
case PGP_PKA_DSA:
return pgp_write_mpi(output, seckey->key.dsa.x);
case PGP_PKA_RSA:
case PGP_PKA_RSA_ENCRYPT_ONLY:
case PGP_PKA_RSA_SIGN_ONLY:
if (!pgp_write_mpi(output, seckey->key.rsa.d) ||
!pgp_write_mpi(output, seckey->key.rsa.p) ||
!pgp_write_mpi(output, seckey->key.rsa.q) ||
!pgp_write_mpi(output, seckey->key.rsa.u)) {
return 0;
}
break;
case PGP_PKA_ELGAMAL:
return pgp_write_mpi(output, seckey->key.elgamal.x);
default:
(void) fprintf(stderr, "Bad seckey->pubkey.alg\n");
return 0;
}
/* close rather than pop, since its the only one on the stack */
pgp_writer_close(output);
pgp_teardown_memory_write(output, mem);
/* should now have checksum in seckey struct */
/* test */
if (pgp_get_debug_level(__FILE__)) {
test_seckey(seckey);
}
return 1;
}